Multiple tray pusher furnace

ABSTRACT

A heat treating furnace has a work path therethrough along which trays carrying work pieces are pushed by a plurality of snake chain conveyors disposed serially along the work path in alternating pairs and single conveyors. A single conveyor will push a tray along a portion of the work path and a pair of conveyors will push the tray along the next succeeding portion of the work path.

United States atet 1191 Wentworth Nov. 26, 1974 [5 MULTIPLE TRAY PUSHER FUACE 2,891,659 6/1959 Westeren 214 23 x [75] Inventor: Hobart L. Wentworth, Barrington,

In? Primary ExaminerRobert G. Sheridan [73] Assignee: Sola Basic Industries, Inc., ney, Agent, or FirmSmythe & Moore Milwaukee, Wis.

22 Fl (1: 17 1974 t 1 1e Jan 57 ABSTRACT [21] Appl. No.: 434,101

1 A heat treating furnace has a work path therethrough [52] Us Cl 214/24 198/82 198/221 along which trays carrying work pieces are pushed by 214/34: 432/128 a plurality of snake chain conveyors disposed serially [51] int. c1. 1 27b 9/38 along the Path in alternating Pm and Single [58] Field of Search 214/23 24 34- 432/128 cmveyms- A Single conveyor Push almg a 198/82 portion of the work path and a pair of conveyors will push the tray along the next succeeding portion of the [56] References Cited work path UNITED STATES PATENTS 5 Claims 6 Drawing Figures 647,347 4/1900 Wellman et al 214/34 y/y/y V/4////1 a/ 7A//7/D///%//% 1' MULTIPLE TRAY PUSI-IER FURNACE The present invention relates to a materials handling device for heat treating furnaces and the like, and more particularly, to a pusher type arrangement for pushing trays along a work path.

Pusher type furnaces of relatively long lengths have long been used for carbonizing, normalizing, and other long-cycle metallurgical and heat treating processes. Many of these processes have been carried out by loading the work pieces on trays which were then pushed through the fumace on refractory or metal skid rails. A row of trays was pushed one against the other in a long row through the furnace with the speed of the trays being such that a single tray remained in the furnace a sufficient time for the process to be completed on the work pieces held thereby. The size of the trays, the load of each individual tray, and the length of a row of trays was limited by the ability of the heated tray to withstand the load at the charged end and the ability of the long row of trays to push the load without one or more trays buckling upwardly. Such limitations greatly restricted the construction and use of long, heavily loaded, multiple tray pusher furnaces both on skids and on rollers.

One of the objects of the present invention is to provide an improved multiple tray pusher furnace.

Another of the objects of the present invention is to provide an improved materials handling device particularly adapted for heat treating furnaces and the like.

Another of the objects of the invention is to provide a multiple tray pusher furnace having a plurality of pusher units along a work path so that gaps are provided between successive trays moving there along.

According to one aspect of the present invention, a materials handling device for a multiple tray pusher furnace may comprise a plurality of snake chain conveyors disposed serially in alternating pairs and single conveyors along a work path. A pusher head is provided on each conveyor to push a tray along the work path. The conveyors are so staggered that a single conveyor will push a tray along a portion of the work path and a pair of conveyors will push the tray along the next succeeding portion of the work path so that the individual trays do not push against each other but gaps or spaces are formed therebetween.

Other objects, advantages and features of the present invention will become apparent from the accompanying description and drawings, which are merely exemplary.

In the drawings:

FIG. 1 is a side elevational view of a heat treating furnace incorporating the materials handling device according to the present invention with portions of the furnace wall being removed;

FIG. 2 is a top plan view of the furnace of FIG. 1 with a portion of the wall being removed to illustrate the arrangement of the conveyors within the furnace;

FIG. 3 is a side elevational view of several of the snake conveyors according to the present invention and shown in enlarged scale;

FIG. 4 is a sectional view taken along the line 44 of FIG. 2;

FIG. 5 is a schematic view illustrating the progress of work trays along the pusher furnace at various stages thereof; and

FIG. 6 is a side elevational view of several of the snake type conveyors according to the present invention and illustrating the positioning of the trays thereon.

Proceeding next to the drawings wherein like reference symbols indicate the same parts throughout the various views, a specific embodiment of the present invention will be described in detail.

In FIG. 1, as indicated generally at 10, a metallurgical or heat treating furnace incorporating the present invention is shown. The furnace 10 is provided with a plurality of heat treating chambers 11 and 12 separated by doors l3, l4 and as is known in the art. The furnace is of the pusher type in which work pieces, such as A and B, mounted on tray 16 and 17 are pushed through the furnace by pusher means which in the present embodiment comprise a plurality of snake chain conveyors such as 18 and 19 arranged in a manner to be presently described.

A snake chain conveyor, such as 18, is known in the art and comprises a plurality of interconnected links each having a roller thereon for movement in a track 20, the lower portion 21 of which is closed and the upper portion 22 of which has a slot therein as may be seen in FIGS. 2 and 4. The end of the interconnected links is provided with a pusher head 23 which extends outwardly through the slot 24 and is nested in a recess or pocket 25 formed in the furnace frame so that the head is disposed below the level of the furnace to allow trays to move over the pusher head.

According to the present invention, the conveyors are arranged serially in alternating pairs as shown at 18 and as single conveyors as shown at 19. This same staggered arrangement is continued along the length of the work path in the manner as illustrated in FIG. 5. Thus, each conveyor or pair of conveyors pushes the work tray along a portion of the work path and the trays will be spaced from each other as they move through the furnace.

According to the present embodiment of the invention, the work path is divided into portions corresponding to the several chambers 11 and 12 of the heat treating furnace. Thus, the pair of conveyors l8 and 18A push the tray 16 through the chamber 11. Upon emerging therefrom through the opened gate 14, the tray will then be urged along through the chamber 12 by the conveyor 19.

As can be seen in FIG. 5, proceeding from the top to the bottom thereof, the progress of trays along the conveyor arrangement of the present invention is illustrated.

The conveyor system according to the present invention provides an individual pusher head with a large pushing face so that a heavily loaded large hot tray will not be deformed by the necessary force required to move the tray. Each pusher head disappears below the level of the tray support to enable a preceeding tray to be moved thereover. In addition, the pusher is removed from the maximum temperature zone when not actually pushing a tray through the furnace. The conveyor mechanism does not adversely effect the atmosphere of the furnace and conditions within the furnace can be closely controlled. The gaps between successive trays in a row or line of trays moving through the furnace enables atmosphere and temperature zoning to be carried out, if desired, by lowering insulated doors between tray positions.

A further advantage of the present invention is that large heavier trays carrying considerably heavier payloads can be moved through a furnace with this conveyor arrangement.

It will be understood that various details of construction and arrangement of parts may be made without departing from the spirit of the invention except as defined in the appended claims.

What is claimed is:

l. A materials handling device comprising a plurality of snake chain conveyors disposed serially in alternating pairs and single conveyors along a work path, each of said conveyors comprising a track having curved and straight portions with a straight portion extending along the work path and the remaining portions extending below said work path, a plurality of interconnected link means for movement in said track and a pusher head attached to said link means adjacent an end and extending upwardly to push a tray along the work path,

said conveyors being staggered such that a single conveyor will push along a portion of the work path and a pair of conveyors will push along the next succeeding portion of the work path.

2. A materials handling device as claimed in claim 1 wherein said conveyors are spaced serially and provide gaps between trays pushed along the work path.

3. A materials handling device as claimed in claim 1 and comprising a heat treating furnace with said work path passing therethrough.

4. A materials handling device as claimed in claim 3 wherein said heat treating furnace comprises a plurality of heating chambers, one of a single or pair of conveyors being disposed in each chamber.

5. A materials handling device as claimed in claim 1 and means defining recesses below said work path to receive pusher heads to allow a tray or the like to pass thereover. 

1. A materials handling device comprising a plurality of snake chain conveyors disposed serially in alternating pairs and single conveyors along a work path, each of said conveyors comprising a track having curved and straight portions with a straIght portion extending along the work path and the remaining portions extending below said work path, a plurality of interconnected link means for movement in said track and a pusher head attached to said link means adjacent an end and extending upwardly to push a tray along the work path, said conveyors being staggered such that a single conveyor will push along a portion of the work path and a pair of conveyors will push along the next succeeding portion of the work path.
 2. A materials handling device as claimed in claim 1 wherein said conveyors are spaced serially and provide gaps between trays pushed along the work path.
 3. A materials handling device as claimed in claim 1 and comprising a heat treating furnace with said work path passing therethrough.
 4. A materials handling device as claimed in claim 3 wherein said heat treating furnace comprises a plurality of heating chambers, one of a single or pair of conveyors being disposed in each chamber.
 5. A materials handling device as claimed in claim 1 and means defining recesses below said work path to receive pusher heads to allow a tray or the like to pass thereover. 